Stability series for the complexation of six key siderophore functional Groups with uranyl using density functional theory

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Title: Stability series for the complexation of six key siderophore functional Groups with uranyl using density functional theory
Authors: Kirby, ME
Sonnenberg, JL
Simperler, A
Weiss, DJ
Item Type: Journal Article
Abstract: Determining stability constants of uranyl complexes with the principal functional groups in siderophores and identifying stability series is of great importance to predict which siderophore classes preferentially bind to UVI and hence impact uranium speciation in the environment. It also helps to develop resins for scavenging UVI from aqueous solutions. Here, we apply a recently developed computational approach to calculate log β values for a set of geochemically relevant uranium organometallic complexes using Density Functional Theory (DFT). We determined the stability series for catecholate, hydroxamate, α-hydroxycarboxylate, α-aminocarboxylate, hydroxy-phenyloxazolonate, and α-hydroxyimidazole with the uranyl cation. In this work, the stability constants (log β110) of α-hydroxyimidazolate and hydroxy-phenyloxazolonate are calculated for the first time. Our approach employed the B3LYP density functional approximation, aug-cc-pVDZ basis set for ligand atoms, MDF60 ECP for UVI, and the IEFPCM solvation model. DFT calculated log β110 were corrected using a previously established fitting equation. We find that the siderophore functional groups stability decreases in the order: α-hydroxycarboxylate bound via the α-hydroxy and carboxylate groups (log β110 = 17.08), α-hydroxyimidazolate (log β110 = 16.55), catecholate (log β110 = 16.43), hydroxamate (log β110 = 9.00), hydroxy-phenyloxazolonate (log β110 = 8.43), α-hydroxycarboxylate bound via the carboxylate group (log β110 = 7.51) and α-aminocarboxylate (log β110 = 4.73). We confirm that the stability for the binding mode of the functional groups decrease in the order: bidentate, monodentate via ligand O atoms and monodentate via ligand N atoms. The stability series strongly suggests that α-hydroxyimidazolate is an important functional group that needs to be included when assessing uranyl mobility and removal from aqueous solutions.
Issue Date: 26-Mar-2020
Date of Acceptance: 1-Feb-2020
DOI: 10.1021/acs.jpca.9b10649
ISSN: 1089-5639
Publisher: American Chemical Society (ACS)
Start Page: 2460
End Page: 2472
Journal / Book Title: The Journal of Physical Chemistry A
Volume: 124
Issue: 12
Copyright Statement: © 2020 American Chemical Society. This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Physical Chemistry A, after peer review and technical editing by the publisher. To access the final edited and published work see
Sponsor/Funder: Natural Environment Research Council (NERC)
Funder's Grant Number: NE/L000660/1
Keywords: Science & Technology
Physical Sciences
Chemistry, Physical
Physics, Atomic, Molecular & Chemical
0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics
0306 Physical Chemistry (incl. Structural)
0307 Theoretical and Computational Chemistry
Publication Status: Published
Embargo Date: 2021-02-24
Article Number: acs.jpca.9b10649
Online Publication Date: 2020-02-24
Appears in Collections:Faculty of Engineering
Earth Science and Engineering
Grantham Institute for Climate Change